The invention relates to a single-use injector with a housing comprising at least one press rod, with a cylinder/piston unit, with a piston actuating plunger, with a triggering unit and with a spring energy store, the triggering unit initially interlocking the pre-tensioned spring energy store by means of the press rod, the press rod sliding, on triggering, along at least one triggering element of the triggering unit and, after triggering of the triggering unit, the spring energy store displacing the press rod and actuating the cylinder/piston unit by means of the piston actuating plunger.
A single-use injector of this type is known from the subsequently published DE 10 2007 034 871. If this injector is exposed with too little pressure acting on the injection site, there is the risk that injection solution will escape in the lateral direction relative to the axis of the injection jet. This leads to what is known as a wet shot.
EP 1 336 419 A1 discloses a jet injector comprising a housing, a fluid chamber, a piston, a force-generating source, an activation element for activating the force-generating source and a needle protection which is arranged at the distal end of the housing for covering a needle.
U.S. 2002/0099329 A1 discloses a gas operated needle-less injection device wherein, by an axial displacement of a cap, a hollow needle is pressed into a gas cartridge.
DE 10 2005 062 206 B3 discloses a single-use injector with a housing in which at least a mechanical spring energy store, at least one cylinder-piston unit which can at least temporarily be filled with an effective substance, at least a piston operating plunger and at least a release unit are arranged. Herein, the spring energy store comprises a pre-tensioned spring element which is held in a pre-tensioned position by a pull means which at least partially extends around the spring element. The release unit further comprises a cutting tool which, for the release of energy of the spring energy store, severs or weakens the pull means at at least one location wherein weakening causes an immediate rupture of the pull means.
The object of the present invention is therefore based on the problem of developing a single-use injector, use of which ensures the required minimum contact force.